Joint for tubular elements

ABSTRACT

Joint between a pipe socket and a pipe male end. A sealing element is radially compressed between the male end and a rabbet in the socket. An annular transverse flange defines an inner transverse end face of the rabbet and has an opening for centering the male end. A retaining ring for the sealing element is fixed to the entrance portion of the socket and has a frustoconical inner portion which fills a frustoconical cavity in the socket between the entrance and the sealing element.

tilted States 'atent 11 1 1111 3,7 ram 1 Oct. 16, 1973 [54] JOINT FORTUBULAR ELEMENTS 3,092,404 6/1963 MacWilliam 285/356 X [75] Inventor:Georges Eugene Bram, FOREIGN PATENTS OR APPLICATIONS POm-a-MOUSSOH,France 963,304 12/1949 France 285/356 7 Assigneec Societe Des FonderiesDe 1,023,421 12/1952 France 285/352 Pont-A-Mousson, Nancy, FrancePrimary Examiner-Mervin Stein [22] Filed: June 4, 1971 AssistantExaminer-David H. Corbin [21] Appl. No.: 150,059 Att0rney-J.Delattre-Seguy [30] Foreign Application Priority Data [57] ABSTRACT June16, 1970 France 7022036 Joint between a p p Socket and a P p male Asealing element is radially compressed between the [52] U.S. Cl 285/231,285/356, 285/376, male end and a rabbet in the socket. An annular trans-2g5/332 7 verse flange defines an inner transverse end face of 51 Int.Cl. F16121/02 the rebbet and has an Opening for Centering the male 58Field Of Search 285/212, 231, 339, A retaining ring for the Sealingelement is fixed to 285/356, 376, 382.7; 277/101, 102, 207 A theentrance portion of the socket and has a frustoconical inner portionwhich fills a frustoconical cavity 5 References Cited in the socketbetween the entrance and the sealing el- UNITED STATES PATENTS emen"2,138,135 11/1938 Boucher 285/356 X 8 Claims, 6 Drawing FigureszlzlllQllEl Jy y 2 Sheets-Sheet .L

Patented Oct. 16, 1973 A-HuM wy Patented Oct. 16, 1973 H-H-u 1740/ JOINTFOR TUBULAR ELEMENTS The present invention relates to a joint for pipesand other tubular elements having a socket and a smooth male end, to amethod of assembling the joint and to the socket and sealing elementforming part of the joint.

Joints are known for pipes having a socket and a male end and includinga sealing element which is radially compressed between the face of arecess in the socket and the male end. In this joint, the sealingelement has in the free uncompressed state an inside diameter less thanthe outside diameter of the male end so that when the male end isinserted in the socket, previously provided with the sealing element, itis necessary to exert great force to cause the male end to enter thesocket and produce a radial compression of the sealing element by anautomatic clamping of said element between the outer face of the maleend and the inner face of the recess in the socket. Serious difficultiesare met with when assembling this type of joint, in particular when thetubular elements (pipes, couplings or elbows) are composed of a heavymaterial, for example iron, and have large diameters. It is then indeeddifficult to cause the male end to penetrate the socket since thispenetration requires considerable force difficult to exert. Further, itis difficult to maintain the tubular elements to be assembled inalignment, particularly in the case of couplings. I

An object of the present invention is to overcome these drawbacks and topermit an easy assembly of the male end with the socket irrespective ofthe dimensions and weights of the pipes, couplings or elbows to beassembled.

The invention provides a method for assembling a joint for tubularelements (pipes, couplings, elbows) one of which has a smooth male endand the other a socket, a sealing element being radially compressedtherebetween, comprising first putting the two tubular elements in thecorrect relative positions while centering the male end in the socket,then placing the sealing element in a recess in the socket whileradially compressing the sealing element.

The relative positioning of the two tubular elements is thereforecarried out without acting on the sealing element and consequentlywithout exertion of force.

If the pipe or other element having a smooth male end comprises at itsother end a socket, the sealing element is first placed in an initialposition on the male end after which the latter is inserted in thesocket of the other element and finally the sealing element is forcedinto its final position in the recess of the socket.

In any case, the sealing element is compressed radially by forcing it toslide longitudinally against a frustoconical face which prolongs theface of the recess provided in the socket for the sealing element.

Another object of the invention is to provide a tubular element (pipe,coupling or elbow) having a socket adapted and arranged for carrying outthe abovedefined method.

The tubular element according to the invention comprises a socket whichhas at its entrance means for fixing a retaining ring for retaining thesealing element in the socket and, axially adjacent said retainingmeans, an inwardly convergent frustoconical face in the socket which isaxially adjacent a rabbet which constitutes a recess for the sealingelement and has an inner end face defined by a transverse flange.

Another object of the invention is to provide a joint between a socketand a male end of two tubular elements assembled by the above-definedmethod and comprising, with said socket and said male end, a sealingelement and a retaining ring for said element, said socket having at itsentrance means for fixing said retaining ring, and axially adjacent saidfixing means, an inwardly cnvergent frustoconical face axially adjacenta rabbet which constitutes a recess in which said sealing element islocated and radially compressed, said recess having an inner end facedefined by a transverse flange which also defines a circular opening forcentering the male end and having a diameter slightly greater than theoutside diameter of the male end, the retaining ring being ofcylindrofrustoconical shape so as to fill the part of the frustoconicalface of the recess when the retaining ring is placed axially adjacentsaid sealing element.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawings.

In the drawings FIG. 1 is an axial sectional view of a joint accordingto the invention before the sealing element is inserted therein FIG. 2is a similar sectional view of the finished joint, and

FIGS. 3 6 are half axial sectional views of modifications of jointsaccording to the invention.

In the embodiment shown in FIGS. 1 and 2, the invention is shown to beapplied to the fluidtight assembly of a smooth male end 1 of a pipe,pipe section or other tubular element T with a socket 2 of another pipe,pipe section or tubular element T with interposition of a sealingelement G.

The socket 2 has internally and axially adjacent its entrance, an innerscrewthread 3 having a diameter a. This screw-thread is connected by afirst socket portion which has a convergent frustoconical face 4 havingat its outer or entrance end a diameter equal to a and at its inner enda diameter less than a to a second cylindrical cylindrical socketportion or inner rabbet 5 having a diameter b. A flange 6 having aninside diameter c a little greater than the outside diameter d of themale end 1 of the pipe T and substantially less than the diameter bdefines by its transverse face 7 the inner face of the rabbet 5.

The sealing element G in an uncompressed state has a barrel-shapedradial cross section, that is, it has an inner annular face 8 andan-outer annular face 9 which are crowned and defined by two parallelplane faces '10, 11, which are transversely disposed with respect to theaxis X-X of the joint. The dimensions of the sealing element are suchthat when in its uncompressed state its minimum outside diameter is inthe neighbourhood of the inside diameter d of the male end 1 and itsmaximum outside diameter exceeds the diameter b of the rabbet 5 of thesocket.

Closing or retaining means are provided at the entrance of the socket.These means comprise a ring 12 having an outer screwthread 13 whosediameter a is such that it can be screwed into the screwthread 3 of thesocket 2 of the pipe T. The ring has a trapezoidal radialcross-sectional shape and an inside diameter e which is slightly greaterthan the outside diameter d of the male end 1.

To assemble the joint, the ring 12 and then the sealing element G arefirst engaged on the male end 1 of the pipe T. These elements easilyslide on this male end. The male end is then inserted in the socket 2 ofthe pipe T. This insertion is easy and requires no appreciable thrust.The flange 6 centers the pipes T and T When these pipes have been put intheir correct relative positions in the joint (FIG. 1), the sealingelement G is forced in the annular recess or rabbet(after this sealingelement has previously been coated with a lubricant) by means of somethrust exerting tool which bears against the face 11 of the element andurges it into the socket without rolling the element. The frustoconicalface 4 facilitates the progressive radial compression of the element Gand its introduction into the rabbet 5. After having withdrawn the toolwhich had served to insert the sealing element, the screwthreadedportion of the ring 12 is screwed into the screwthreaded portion 3. Theentrance of the socket is thus closed and the joint is in its finalstate as shown in FIG. 2.

Consequently, if the sealing element G is subjected to a very highpressure on the part of the fluid within the pipes, it cannot beexpelled from the rabbet 5. The sealing between the two pipes is ensuredowing to the radial compression of the sealing element in the spacedefined by the end face 7 of the flange 6 and the outer face of thesmooth male end 1 of the pipe T.

As can be seen, by means of the invention it is easy to insert the maleend 1 in the socket 2 and then place the sealing element G in positionby exerting an axial thrust thereon. This is of particular advantage inthe case of the laying of pipes of large diameter since, owing to theirweight, they are difficult to handle. Now, as the sealing element isplaced in position subsequent to the final positioning of the pipes, itdoes not render the handling of the pipe T more difficult.

Further, the joint obtained is of use in the case of the assembling ofcouplings or short elbows in which it is difficult to maintain thealignment of the parts during the fitting.

The joint is of universal utility, since it is possible to employ it forpipes of large or small diameters or for couplings or elbows.

It is possible to effect modifications in the joint according to theinvention. Thus, the retaining ring 12 may be replaced by a. a ring 12a(FIG. 3) having bayonet fixing means maintained by inner lugs 13 insteadof the screwthreading 13 of the first embodiment, the inside diameter ofthe lugs being greater than the outside diameter of the sealing elementG in the uncompressed state of the latter b. a ring 12b orcounter-flange 14 (FIG. 4) which is screwthreaded externally or hookedto the socket 2 by hook members 15 a split ring 12c (FIG. 5) which isresiliently yieldable and so shaped that it is tightened around the maleend of pipe T under the effect of the tapered face 4 and thus hooksthrough an inner toothed portion 16 into an outer recess 17 formed inthe male end 1 of the pipe T so that this pipe is locked in position. Anannular safety plate 18 can be fixed by bolts 19 to the socket.

Further, it is possible, as shown in FIG. 6, to employ a ring 12d asthrust means for exerting a thrust on the sealing element after the maleend 1 of the pipe T has been inserted in the socket 2 of the pipe T.This trapezoidal ring has a cylindrical extension 20 having inside andoutside diameters respectively greater than the outside diameter of themale end of the pipe and less than the inside diameter of the rabbet 5so as to exert a thrust on the face 11 of the sealing element G.

The sealing element described can be replaced by an 0-section sealingelement but in this case when it is inserted in the rabbet 5 it issubjected to internal deformations and stresses which may impair itsperformance over a period of time.

Having now described my invention what I claim and desire to secure byLetters Patent is 1. In a joint comprising a socket having an entranceend and integral with a first pipe section, a male end of a second pipesection coaxial with said socket, a sealing element interposed betweensaid socket and said male end, a retaining ring for retaining saidsealing element in axial position in said socket, and means for fixingsaid ring axially in position in said socket; the following featuressaid socket has a first inner portion adjacent said entrance end anddefining a frustoconical face inwardly convergent to a small end remotefrom said entrance end, a second inner portion defining a firstcylindrical face connected to said small end of said frustoconical faceand defining with said male end an annular space, and a third innerportion adjoining said second portion and defining a second cylindricalface having a diameter less than the diameter of said first cylindricalface and slightly greater than the outside diameter of said male end forcentering said male end in said socket, said sealing element is locatedin said annular space and is in engagement with said male end and saidfirst cylindrical face and in a compressed condition radially of saidsocket and free to expand axially of said socket, and said retainingring defines an end face which extends radially of said annular space inthe region of said connection of said first cylindrical face to saidsmall end of said frustoconical face and acts as an axial abutment forretaining said sealing element in said second portion of said socket.

2. A joint as claimed in claim 1, wherein said frustoconical face hasadjacent said entrance end a diameter exceeding the outside diameter ofthe sealing element in a free uncompressed state of the sealing elementand at said connection to said first cylindrical face a diameter lessthan said outside diameter of the sealing element in said freeuncompressed state.

3. A joint as claimed in claim 1, wherein said sealing element is awasher which has in an uncompressed state a barrel-shaped radial crosssection, said crosssectional shape being defined by crowned inner andouter faces and two parallel plane faces transverse to the axis of thewasher.

4. A joint as claimed in claim 1, wherein said means for fixing theretaining ring are screwthreaded means.

5. A joint as claimed in claim 1, wherein said means for fixing theretaining ring is a bayonet device.

6. A joint as claimed in claim 1, wherein said means for fixing theretaining ring is a counterflange and means for hooking saidcounterflange to said socket.

7. A joint as claimed in claim 1, wherein said means for fixing theretaining ring is a split ring having an inner toothed portion which isheld in engaged relation 8. A joint as claimed in claim 12, wherein saidretaining ring has an outer frustoconical face which is substantiallyco-extensive with and engages said frustoconical face of said firstportion of said socket.

1. In a joint comprising a socket having an entrance end and integralwith a first pipe section, a male end of a second pipe section coaxialwith said socket, a sealing element interposed between said socket andsaid male end, a retaining ring for retaining said sealing element inaxial position in said socket, and means for fixing said ring axially inposition in said socket; the following features : said socket has afirst inner portion adjacent said entrance end and defining afrustoconical face inwardly convergent to a small end remote from saidentrance end, a second inner portion defining a first cylindrical faceconnected to said small end of said frustoconical face and defining withsaid male end an annular space, and a third inner portion adjoining saidsecond portion and defining a second cylindrical face having a diameterless than the diameter of said first cylindrical face and slightlygreater than the outside diameter of said male end for centering saidmale end in said socket, said sealing element is located in said annularspace and is in engagement with said male end and said first cylindricalface and in a compressed condition radially of said socket and free toexpand axially of said socket, and said retaining ring defines an endface which extends radially of said annular space in the region of saidconnection of said first cylindrical face to said small end of saidfrustoconical face and acts as an axial abutment for retaining saidsealing element in said second portion of said socket.
 2. A joint asclaimed in claim 1, wherein said frustoconical face has adjacent saidentrance end a diameter exceeding the outside diameter of the sealingelement in a free uncompressed state of the sealing element and at saidconnection to said first cylindrical face a diameter less than saidoutside diameter of the sealing element in said free uncompressed state.3. A joint as claimed in claim 1, wherein said sealing element is awasher which has in an uncompressed state a barrel-shaped radial crosssection, said cross-sectional shape being defined by crowned inner andouter faces and two parallel plane faces transverse to the axis of thewasher.
 4. A joint as claimed in claim 1, wherein said means for fixingthe retaining ring are screwthreaded means.
 5. A joint as claimed inclaim 1, wherein said means for fixing the retaining ring is a bayonetdevice.
 6. A joint as claimed in claim 1, wherein said means for fixingthe retaining ring is a counterflange and means for hooking saidcounterflange to said socket.
 7. A joint as claimed in claim 1, whereinsaid means for fixing the retaining ring is a split ring having an innertoothed portion which is held in engaged relation to a cavity in saidsecond element by the resilient deformation of said ring produced bysaid frustoconical face engaged with said split, said cavityconstituting stop means preventing extraction of said male end from saidsocket.
 8. A joint as claimed in claim 12, wherein said retaining ringhas an outer frustoconical face which is substantially co-extensive withand engages said frustoconical face of said first portion of saidsocket.